# US 10,371,128 B2 · Compliant actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,128 B2 - Document ID: US10371128B2 - Status: Granted - Kind: B2 - Application number: 15/307,730 - Filed: 2015-04-23 - Published: 2017-02-23 - Granted: 2019-08-06 - Earliest claimed: 2014-04-29 - Assignees: University of Dundee - Applicants: University of Dundee - Inventors: Luigi Manfredi; Alfred Cuschieri - Web page: https://patentgrep.com/patent/US10371128B2 ## CPC - A61B 1/0055: {Constructional details of insertion parts, e.g. vertebral elements} - A61B 1/0057: {Constructional details of force transmission elements, e.g. control wires} - A61B 1/0058: {using shape-memory elements} - A61B 34/30: Surgical robots - F03G 7/06143: {Wires} - F03G 7/0633: {performing a rotary movement} - A61B 2034/301: {for introducing or steering flexible instruments inserted into the body, e.g. catheters or endoscopes} - A61B 2034/303: {specifically adapted for manipulations within body lumens, e.g. within lumen of gut, spine, or blood vessels} - F03G 7/066: {Actuator control or monitoring} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - F03G: SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR (arrangements in connection with power supply in vehicles from force of nature B60K16/00; electric propulsion with power supply in vehicles from force of nature B60L8/00) ## Abstract An actuator (12) includes a moving member (18) pivotally connected to a base unit (14) for rotation about an axis. The driving force for rotation of the moving member (18) relative to the base unit (14) is provided by a pair of antagonistically operating shape memory alloy (SMA) wires (48, 50) and transmitted via a torsional spring (56). An endoscope, or a snake-like robot (66), may include one or more of the actuators (12). ## Claims ### Claim 1 An actuator comprising: a moving member pivotally connected to a base unit for rotation about an axis; wherein the driving force for rotation of the moving member relative to the base unit is provided by a pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring. ### Claim 2 (depends on 1) The actuator of claim 1 wherein the pair of antagonistically operating SMA wires are mounted within the body of the actuator. ### Claim 3 (depends on 2) The actuator of claim 2 wherein the pair of antagonistically operating SMA wires or the bulk of the pair of antagonistically operating SMA wires are mounted within the moving member. ### Claim 4 (depends on 2) The actuator of claim 2 wherein the pair of antagonistically operating SMA wires or the bulk of the pair of antagonistically operating SMA wires are mounted within the base unit. ### Claim 5 (depends on 1) The actuator of claim 1 wherein the pair of antagonistically operating SMA wires are coiled or wound round within the body of the actuator. ### Claim 6 (depends on 5) The actuator of claim 5 wherein the pair of antagonistically operating SMA wires run around a plurality of pulleys within the body of the actuator. ### Claim 7 (depends on 6) The actuator of claim 6 wherein the pair of antagonistically operating SMA wires run around a plurality of pulleys mounted within the body of the moving member. ### Claim 8 (depends on 1) The actuator of claim 1 wherein the moving member and base unit are hollow or comprise frame structures having open space within. ### Claim 9 (depends on 1) The actuator of claim 1 wherein the pair of SMA wires drives a wheel or shaft mounted in the actuator body and rotating on the rotation axis; and wherein the rotation of the wheel or shaft is transmitted to the joint between the base unit and the moving member via the torsional spring. ### Claim 10 (depends on 9) The actuator of claim 9 wherein the torsional spring is in the form of a wire engaging at one end with the wheel or shaft and the other with the base unit. ### Claim 11 (depends on 1) The actuator of claim 1 wherein the torsional spring is coiled or looped around the rotation axis. ### Claim 12 (depends on 1) The actuator of claim 1 wherein the torsional spring is a rod or bar of a resiliently flexible material that twists as torque is applied. ### Claim 13 (depends on 1) The actuator of claim 1 wherein the torsional spring is a magnetic torsional spring. ### Claim 14 (depends on 13) The actuator of claim 13 wherein the magnetic torsional spring comprises a circular array of permanent magnets is mounted on the wheel or shaft driven by the SMA wires and a corresponding circular array of permanent magnets is mounted about the rotation axis on the base unit. ### Claim 15 (depends on 1) The actuator of claim 1 wherein the actuator body is cylindrical or generally cylindrical. ### Claim 16 (depends on 1) The actuator of claim 1 wherein the base unit comprises a circular or generally circular ring. ### Claim 17 (depends on 16) The actuator of claim 16 wherein the moving member comprises a frame having a circular or generally circular end, distal to the ring and connecting to the ring by means of two longitudinally extending connector arms which attach to diametrically opposite pivot positions on the ring. ### Claim 18 (depends on 1) The actuator of claim 1 wherein the SMA wires comprise an NiTi alloy. ### Claim 19 (depends on 1) The actuator of claim 1 wherein a distributed power and control system is employed. ### Claim 20 (depends on 1) The actuator of claim 1 comprising two moving members. ### Claim 21 (depends on 20) The actuator of claim 20 wherein the two moving members are disposed to either side of the base unit, each of the moving members being independently pivotally connected to the base unit for rotation about an axis transverse to the longitudinal axis of the actuator; and wherein the driving force for rotation of each moving member relative to the base unit is provided by a pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring, for each moving member. ### Claim 22 (depends on 21) The actuator of claim 21 wherein the rotation axes of the two moving members are at right angles to each other, providing two degrees of freedom to the motion of the actuator. ### Claim 23 (depends on 21) The actuator of claim 21 wherein the rotation axes of the moving members are at right angles to each other and intersect. ### Claim 24 (depends on 21) The actuator of claim 21 wherein one moving member is pivotally connected to the base unit for rotation about the longitudinal axis and the rotation relative to the base unit is driven by means of a further pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring. ### Claim 25 (depends on 24) The actuator of claim 24 wherein both moving members are pivotally connected to the base unit for rotation about the longitudinal axis and for each moving member the rotation relative to the base unit is driven by means of a further pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring. ### Claim 26 (depends on 1) The actuator of claim 1 wherein an end of a moving member distal to the base unit has connector arms that project away from the base unit, for pivotal connection to another base unit. ### Claim 27 An endoscope or a snake-like robot comprising at least one actuators; the actuator comprising a moving member pivotally connected to a base unit for rotation about an axis; wherein the driving force for rotation of the moving member relative to the base unit is provided by a pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring. ### Claim 28 An endoscope or a snake-like robot comprising a plurality of actuators, connected together; each actuator of the plurality of actuators comprising a moving member pivotally connected to a base unit for rotation about an axis; wherein the driving force for rotation of the moving member relative to the base unit is provided by a pair of antagonistically operating shape memory alloy (SMA) wires and transmitted via a torsional spring. ### Claim 29 (depends on 28) An endoscope or a snake-like robot according to claim 28 wherein the plurality of actuators are joined one to the next by link pieces. ### Claim 30 (depends on 28) An endoscope or a snake-like robot according to claim 28 wherein the plurality of actuators are joined one to the next by attaching ends of moving members, distal to their respective base units, directly together.